Neuroendocrine differentiation in the setting of prostatic carcinoma: contemporary assessment of a consecutive series.

AIM: Clinicopathologic characterisation of a contemporary series of neuroendocrine (NE) differentiation in the setting of prostatic carcinoma (PCa) was examined. METHODS AND RESULTS: We reviewed institutional databases for in-house cases with a history of PCa and histopathologic evidence of NE differentiation during the disease course. In all, 79 cases were identified: 32 primary and 47 metastases. Metastatic lesions were in liver (n = 15), lymph node (n = 9), bone (n = 6), lung (n = 3), brain (n = 1), and other sites (n = 13). In all, 63 of 76 (82%) cases with NE differentiation and available history were posttherapy: six postradiation therapy (RT), 24 post- androgen-deprivation therapy (ADT), and 33 post-RT + ADT. Morphologic assessment (n = 79): (i) 23 pure small-cell/high-grade NE carcinoma (HGNEC): 20/23 metastatic; (ii) 10 combined high-grade PCa and small-cell/HGNEC: 9/10 primary; (iii) 15 PCa with diffuse NE immunohistochemistry (IHC) marker positivity/differentiation, associated with nested to sheet-like growth of cells with abundant cytoplasm and prominent nucleoli, yet diffuse positivity for at least one prostatic and one NE IHC marker: all metastatic; (iv) 11 PCa with patchy NE differentiation, displaying more than single-cell positivity for NE IHC: five primary / six metastatic; (v) nine PCa with focal NE marker positive cells: four primary / five metastatic; (vi) 11 PCa with 'Paneth cell-like' change: all primary. CONCLUSIONS: In this contemporary series, the majority of NE differentiation in the setting of PCa was seen posttherapy. We highlight the tendencies of small-cell/HGNEC and PCa with diffuse NE differentiation by IHC to occur in metastatic settings, while morphologically combined high-grade PCa + small-cell/HGNEC and 'Paneth cell-like' change occur in primary disease.

Immunohistochemistry-based assessment of androgen receptor status and the AR-null phenotype in metastatic castrate resistant prostate cancer.

BACKGROUND: Molecular and immunohistochemistry-based profiling of prostatic adenocarcinoma has revealed frequent Androgen Receptor (AR) gene and protein alterations in metastatic disease. This includes an AR-null non-neuroendocrine phenotype of metastatic castrate resistant prostate cancer which may be less sensitive to androgen receptor signaling inhibitors. This AR-null non-neuroendocrine phenotype is thought to be associated with TP53 and RB1 alterations. Herein, we have correlated molecular profiling of metastatic castrate resistant prostate cancer with AR/P53/RB immunohistochemistry and relevant clinical correlates. DESIGN: Twenty-seven cases of metastatic castrate resistant prostate cancer were evaluated using histopathologic examination to rule out neuroendocrine differentiation. A combination of a hybridization exon-capture next-generation sequencing-based assay (n = 26), fluorescence in situ hybridization for AR copy number status (n = 16), and immunohistochemistry for AR (n = 27), P53 (n = 24) and RB (n = 25) was used to profile these cases. RESULTS: Of 27 metastatic castrate resistant prostate cancer cases, 17 had AR amplification and showed positive nuclear expression of AR by immunohistochemistry. Nine cases lacked AR copy number alterations using next-generation sequencing/fluorescence in situ hybridization. A subset of these metastatic castrate resistant prostate cancer cases demonstrated the AR-null phenotype by immunohistochemistry (five cases and one additional case where next-generation sequencing failed). Common co-alterations in these cases involved the TP53, RB1, and PTEN genes and all these patients received prior therapy with androgen receptor signaling inhibitors (abiraterone and/or enzalutamide). CONCLUSIONS: Our study suggests that AR immunohistochemistry may distinguish AR-null from AR-expressing cases in the metastatic setting. AR-null status informs clinical decision-making regarding continuation of therapy with androgen receptor signaling inhibitors and consideration of other treatment options. This might be a relevant and cost-effective diagnostic strategy when there is limited access and/or limited tumor material for molecular testing.

Conducting a Pathology Research Study, From Start to Finish.

CONTEXT.­: Many pathologists-in-training enter residency or fellowship with either no formal experience in research or with a basic science research background that may not translate well to research in the realm of diagnostic pathology, including surgical pathology, cytopathology, and clinical pathology. OBJECTIVE.­: To provide a starting point and practical framework for residents or fellows who wish to conduct research in these fields. DATA SOURCES.­: Existing literature and the pooled experience of the authors, all academic pathologists. CONCLUSIONS.­: We provide tips and tricks that trainees will find useful when planning and executing pathology research projects. A key component of successful research in diagnostic pathology is active guidance by a skilled faculty mentor, bolstered by enthusiastic, timely work by a highly motivated and dedicated trainee. We hope this advice will improve interactions between trainees and their faculty mentors and enhance the quality of research in diagnostic pathology.

Implementation of Digital Pathology Offers Clinical and Operational Increase in Efficiency and Cost Savings.

CONTEXT.­: Digital pathology (DP) implementations vary in scale, based on aims of intended operation. Few laboratories have completed a full-scale DP implementation, which may be due to high overhead costs that disrupt the traditional pathology workflow. Neither standardized criteria nor benchmark data have yet been published showing practical return on investment after implementing a DP platform. OBJECTIVE.­: To provide benchmark data and practical metrics to support operational efficiency and cost savings in a large academic center. DESIGN.­: Metrics reviewed include archived pathology asset retrieval; ancillary test request for recurrent/metastatic disease; cost analysis and turnaround time (TAT); and DP experience survey. RESULTS.­: Glass slide requests from the department slide archive and an off-site surgery center showed a 93% and 97% decrease, respectively. Ancillary immunohistochemical orders, compared in 2014 (52%)-before whole slide images (WSIs) were available in the laboratory information system-and 2017 (21%) showed $114 000/y in anticipated savings. Comprehensive comparative cost analysis showed a 5-year $1.3 million savings. Surgical resection cases with prior WSIs showed a 1-day decrease in TAT. A DP experience survey showed 80% of respondents agreed WSIs improved their clinical sign-out experience. CONCLUSIONS.­: Implementing a DP operation showed a noteworthy increase in efficiency and operational utility. Digital pathology deployments and operations may be gauged by the following metrics: number of glass slide requests as WSIs become available, decrease in confirmatory testing for patients with metastatic/recurrent disease, long-term decrease in off-site pathology asset costs, and faster TAT. Other departments may use our benchmark data and metrics to enhance patient care and demonstrate return on investment to justify adoption of DP.

Interobserver and intraobserver reproducibility in digital and routine microscopic assessment of prostate needle biopsies.

Advances in whole slide digital imaging in the past decade necessitate validation of these tools in each organ system in advance of clinical adoption. We assessed reproducibility in reporting prostate needle biopsy parameters among urologic pathologists using routine and digital microscopy in a consultation/second opinion-like setting. Four urologic pathologists evaluated a single core level from 50 diagnostically challenging needle biopsy specimens by routine microscopy and whole slide digital imaging. Interobserver and intraobserver agreement were calculated for primary and secondary Gleason grades, Gleason score, tumor quantitation (percentage and size in millimeters), and perineural invasion. Interobserver agreement for routine microscopy was excellent for primary Gleason grade (κ = 0.72) and good for all other parameters (κ ranging from 0.36 to 0.55). Whole slide digital imaging assessment yielded similar agreement for all parameters. Intraobserver agreement for primary Gleason grade and Gleason score was very good to excellent for all pathologists (all κ ≥ 0.65 and ≥ 0.73, respectively). Size of tumor in millimeters consistently displayed higher levels of agreement than percentage of tumor across media and pathologists. Digital assessment of routinely reported cancer parameters on prostatic needle biopsy for a given scanned core level is comparable to that of routine microscopy. These findings imply that histologic interpretation using dynamic whole slide images may accurately simulate routine microscopic evaluation in the consultation setting. Implementation of whole slide digital imaging in these scenarios may significantly reduce the workload of large referral centers in the near future and impact the manner in which pathologists seek second opinion consultation on challenging cases.